Remove banner example from index.mdx and text-refine new page

Author: RebeccaTamachiro

src/content/docs/style-guide/frontmatter/banner.mdx

@@ -9,7 +9,7 @@ import { Steps, FileTree } from "~/components";
 
 One of the fields you can add to the [Frontmatter](/style-guide/frontmatter/) is `banner`. It displays a prominent section at the top of the page and supports the use of HTML for links and formatting.
 
-Only use it to alert about situations that may cause disruptions to users and take note to remove it when applicable.
+Only use it to alert about disruptive situations and take note to remove it when applicable.
 
 ## Example
 

src/content/docs/style-guide/frontmatter/index.mdx

@@ -5,10 +5,6 @@ description: |
     For example, a regular page might set title and description fields.
 sidebar:
     order: 3
-banner:
-    content: |
-        <h2>Hello, world!</h2>
-        <a href="/">Homepage</a>
 ---
 
 Frontmatter contains the metadata for a page, such as the `title`. It is written as YAML, between `---`, at the top of the page.
@@ -23,10 +19,6 @@ description: |
     For example, a regular page might set title and description fields.
 sidebar:
     order: 3
-banner:
-    content: |
-        <h2>Hello, world!</h2>
-        <a href="/">Homepage</a>
 ---
 ```